Pomalidomide plus low-dose dexamethasone (LoDEX) significantly increased progression-free survival and overall survival compared with high-dose dexamethasone (HiDEX) in patients with refractory multiple myeloma, according to the results of a phase III study presented at the 54th Annual Meeting of the American Society of Hematology in Atlanta, Georgia.
Multiple myeloma is a cancer of plasma cells, which are a special type of white blood cell that are part of the body’s immune system. Patients with multiple myeloma have increased numbers of abnormal plasma cells that may produce increased quantities of dysfunctional antibodies detectable in the blood and/or urine. Patients with multiple myeloma who have become refractory—or resistant—to the drugs Revlimid® (lenalidomide) and Velcade® (bortezomib) have limited treatment options. There is no standard treatment for these patients and they typically have a poor prognosis, with a median overall survival of 9 months.
Pomalidomide is an immunomodulatory drug that has shown activity in multiple myeloma patients who have become refractory to Velcade®, Thalomid® (thalidomide), and Revlimid®. It works by directly inhibiting angiogenesis and myeloma cell growth.
Researchers conducted a phase III trial in 455 patients with refractory or relapsed/refractory multiple myeloma. Patients were randomly assigned to receive pomalidomide plus LoDEX (302 patients) or HiDEX alone (153 patients). After a median follow-up of 18 months, the results indicated that patients receiving pomalidomide experienced a significant increase in progression-free survival—15.7 weeks compared to 8 weeks for those receiving HiDEX alone. Overall survival was also improved among patients receiving pomalidomide and LoDEX—the median has not yet been reached, but is expected to be 11-12 months, compared to 35 weeks for patients receiving HiDEX alone.
Based on these results, the researchers discontinued the HiDEX arm because an independent review by the study’s Data Safety Monitoring Board recommended that all patients in the HiDEX arm be switched over to treatment with pomalidomide and LoDEX.
The combination of pomalidomide and LoDEX was well tolerated, although there were some expected toxicities in both groups, including neutropenia (reported in 42% patients receiving pomalidomide/LoDEX and 15% of those receiving HiDEX), thrombocytopenia (21% vs 24%), and fever (7% vs 0%). The primary reason for discontinuation was progressive disease (in 35 vs 49 patients, respectively). Around 25% of patients in both arms died during the study, primarily from progressive disease and infections.
The researchers concluded that pomalidomide plus LoDEX significantly increased progression-free survival and overall survival compared with HiDEX in patients with multiple myeloma refractory to Velcade and Revlimid. Based on these results, the researchers recommend that pomalidomide and LoDEX become the new standard of care in patients who have become refractory to Velcade and Revlimid.
Dimopoulos MA, Lacy MQ, Moreau P, et al. Pomalidomide in Combination with Low-Dose Dexamethasone: Demonstrates a Significant Progression Free Survival and Overall Survival Advantage, in Relapsed/Refractory MM: A Phase 3, Multicenter, Randomized, Open-Label Study. Blood (ASH Annual Meeting Abstracts) 2012 120: Abstract LBA-6.
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